SALT LAKE CITY — New research out of the University of Utah shows post-traumatic stress disorder isn't just a private war for the veteran, but a battle that can impact a spouse just as intensely. Fortunately, that information also suggests helpful strategies for treatment, too.

As many as 25 percent of returning troops from the wars in Iraq and Afghanistan suffer from post-traumatic stress disorder, or PTSD. That's around a half-million Americans.

Researchers have know for some time that PTSD places relationships at risk, but this new research raises red flags for health risks for a spouse or partner.

"It's having an effect beyond the veteran, him or herself," said Dr. Timothy Smith, a psychology professor at the University of Utah who co-authored the study with Catherine Caska. Caska's doctoral dissertation is the basis of the research.

They measured how much blood pressure rose among the couples when they discussed intense issues in their relationships, like money and kids.

"It was quite pronounced in the couples where the veteran has PTSD," Smith said.

The couples affected by PTSD showed greater increases in blood pressure, heart rate and other indicators of cardiovascular health risk in response to the relationship conflict. It suggests these partners may be at similar, if not greater, risk than the veterans for health consequences from PTSD.

Cori Caddel served 20 years in the army. She deployed to Afghanistan in 2006 and was diagnosed with PTSD in 2010.

"There comes a point when things get to be too much, and you just shut down," she said. "Knowing that somebody understands is half the battle."

She said her husband is learning how to work with her when she's having a bad day, and knows when to walk away. But it does not surprise her to hear that her PTSD can affect the mental and physical health of her spouse, too. She said she's seen the impact of her trauma from war on her whole family.

"Not only me," Caddel said, "it affects everybody."

The findings from the study also suggest that couples therapy could be good treatment.

"The problem is getting people to identify that they have a problem, feel comfortable about seeking help and being able to get it," Smith says.

Smith will present the findings at a professional conference in Miami next week.